The Italian Renaissance has never felt as real as when free-running across the rooftops of Florence and Venice, or hobnobbing with the likes of Leonardo da Vinci and Niccolo Machiavelli -- all virtually recreated in the best-selling video game "Assassin's Creed 2." The powerful one-two punch of fiction and historical fact has proven irresistible to at least one Renaissance scholar, who ended up consulting on the next game in the series.

Marcello Simonetta is an Italian raised in Rome who now lives in New York City as an author and scholar. His intimate knowledge of the Italian Renaissance happened to coincide perfectly with the story of "Assassin's Creed 2," where gamers control protagonist Ezio Auditore da Firenze as he nimbly scales Italy's architectural landscape and stalks foes from the rooftops.

"Of course it's a [virtual] construction, but nothing else can give you the beauty of that kind of breathtaking perspective while walking on the rooftops," Simonetta said. "I've been on Florentine rooftops -- not jumping like Ezio -- but I've seen them, and also in Rome and Venice."

But this is no stuffy educational experience. Millions of gamers have already bought into the story, which explores the convoluted politics and conspiracies that riddled the Italian Renaissance. The follow-up game slated for release next Tuesday (Nov. 16), "Assassin's Creed: Brotherhood," looks set to do the same as it follows Ezio to Rome.

"History is unparalleled compared to human imagination." Simonetta said. "No one imagined the [Roman Catholic] pope would send assassins to kill his enemies in a church, but it happened."

The games even give small historical footnotes about the buildings or people that gamers might encounter. But any incidental learning is playful and takes a backseat to gameplay and story, rather than turning into a stuffy educational experience.

Simonetta discovered a startling secret behind that assassination attempt, known as "the Pazzi conspiracy," while writing his second book, "The Montefeltro Conspiracy: A Renaissance Mystery Decoded" (Doubleday, 2008). The plot targeted Lorenzo de Medici, a renowned political leader and arts patron who hailed from a powerful banking family in Florence, and was featured as a mission in "Assassin's Creed 2."

The Pazzi family behind the plot represented banking rivals to the Medici family, and had the support of Pope Sixtus IV for their plan. Assassins struck while Lorenzo de Medici and his brother, Giuliano, were attending Sunday mass on April 26, 1478.

Lorenzo managed to escape death, but his brother Giuliano was killed. But in the game, Lorenzo only escapes with the player's help.

As it turns out, Simonetta found a coded letter that also fingers Frederico de Montefeltro, the Duke of Urbino, as an architect of the assassination attempt. That came as a shocking twist for historians, because Montefeltro was considered one of the Medici's best friends.

There's one pivotal difference between the historical event and the game's depiction — the assassins are shown attacking outside the church, rather than inside as it historically happened. Game developers had decided that staging the event inside of the church would require too much technical work, Simonetta said.

Recreating Rome

Simonetta served as the main historical consultant on the upcoming game "Assassin's Creed: Brotherhood," after being recommended by Margaret Meserve, a colleague and historian at the University of Notre Dame who consulted on "Assassin's Creed 2." The new game continues Ezio's adventures in a virtual Rome that supposedly takes hours to cross in-game.

The famous Roman Colosseum still looms above virtual Rome, but its in-game shape is circular rather than elliptical. That's because the challenge of making different shadows for all sides of the building would have driven game designers nuts, Simonetta said.

"It's fine that you have a Colosseum that's not elliptical, because it looks like the Colosseum," Simonetta told LiveScience. "The fact that you can go inside these buildings [in the game] is incredible."

Rome in 1503 should look similar in architectural style to the city of Florence featured in "Assassin's Creed 2." But the art director for "Assassin's Creed: Brotherhood" decided to give Rome the Baroque architectural style of the late 16th century, so that gamers would have a new-looking virtual playground that is also more recognizable to modern eyes.

Still, Simonetta did raise a scholar's finger of objection when game developers wanted to put the famous Swiss Guard in the game as defenders of the pope. The Swiss Guard was actually hired by the following pope — a major rival to the pope in the game — three years later.

Simonetta also consulted on the historical credibility of the language that game characters speak — a linguistic brew of English and some choice Italian phrases. He added that Italy's locally-translated version of "Assassin's Creed: Brotherhood" may actually tone down the Italian language used, which is historically inaccurate.

The game developers actually ended up avoiding the more graphically violent — but historically authentic — acts of the Renaissance era. (That's not to say that the game is tame.)

"I told them certain details of cruelties and violence that the Borgia [an Italian noble family] were perpetrating, and they considered it too gross for the audience," Simonetta said.

Meet the Italians

Many historical figures are set to return or make appearances in "Assassin's Creed: Brotherhood." Simonetta's favorite returning character is Caterina Sforza, a notably beautiful and courageous woman who fought in armor and earned the nickname "the Tigress of Forli."

Gamers who choose to buy the new game for Sony's PS3 console will also be able to run errands for Nicolaus Copernicus — the Polish astronomer credited with developing the heliocentric theory that says the Earth goes around the sun.

Players can also find political philosopher Niccolo Machiavelli lurking in the game. Perhaps he is observing the main villain as inspiration for his famous book on political intrigue, "The Prince," according to Simonetta.

"I can tell you Machaivelli is portrayed accurately in the sense that you're not quite sure what side he's on," Simonetta said.

One of the most popular characters from "Assassin's Creed 2," a young Leonardo da Vinci, is also set to return in "Assassin's Creed: Brotherhood." He equips the player with all sorts of weapons and gadgets based on the historical da Vinci's sketches and designs.

Da Vinci's character in particular may represent one of best examples of seamlessly combining fact and fiction into a pleasurable experience. His popularity in "Assassin's Creed 2" sparked a series of online message posts where players sympathized over failing to press a button fast enough during a game sequence to give the Italian Renaissance man a manly hug.

"I guess this is how you can tell that you're really connecting with a video game's world and characters, when you genuinely feel bad about missing a somewhat meaningless (from a gameplay standpoint) quick time event," a gamer using the screenname Imperius Rix posted on the forums of the gaming website Giant Bomb. "Sorry, Leo. You know I love you, bro."

Other gamers also expressed their affection for the virtual avatar of the long-dead historical figure.

"Man, when I play this, I can't miss this opportunity," gamer TheGreatGuero posted in response to Imperius Rix. "Leonardo da Vinci is too awesome to not share man hugs with."

The game's sense of intimacy with history has intrigued some educators and scholars, including Simonetta. He still holds out hope that the Assassins Creed series or similar games may eventually become effective learning tools for immersing students in history.

"The freedom that the game gives you is astonishing, and if you're flying with a Leonardo machine it's even better," Simonetta said. "That's the part which could really be retooled for teaching experience."